The vomeronasal organ (VNO) or Jacobson's organ is a chemoreceptor organ
present in most tetrapod species. It is important in intraspecific chemical
(pheromone) communication. The paired organs are separate from the main
olfactory organ. In most species they are largely enclosed within a capsule
formed by the vomer-bone or vomer-cartilage and are found within a bulge
along each side of the base of the nasal septum.